The S&P/TSX composite index slipped 7.56 points to 11,941.7 while the TSX Venture Exchange was ahead 1.84 points to 1,242.58.
The Canadian dollar also finished little changed, down 0.01 of a cent at 101.44 cents US. The loonie could be in for some volatility after Quebecers vote in a new government Tuesday while the Bank of Canada makes its next announcement on interest rates Wednesday.
U.S. markets were mainly lower even as a disappointing reading of a key gauge of the manufacturing sector and lower construction spending raised expectations that the U.S. Federal Reserve will embark on another jolt of stimulus.
The Dow Jones industrials fell 54.9 points to 13,035.94 after the Institute for Supply Management's August index came in at 49.6, a bit weaker than July's reading of 49.8 and below expectations of 50.2, which would have signalled expansion.
Also, construction spending dropped by 0.9 per cent in July against expectations for a slight increase.
The Nasdaq composite index was ahead 8.1 points at 3,075.06 and the S&P 500 index was off 1.64 points to 1,404.94.
"Although today’s PMI report might not prove to be a tipping factor, it certainly runs counter to the substantial and sustainable improvement in economic activity many (Fed) members wanted to observe before pulling the trigger on more monetary stimulus," said TD Bank senior economist Martin Schwerdtfeger.
Investors also looked to employment data for clues as to whether the Fed thinks the U.S. economic recovery needs help in staying on the rails. Economists expect Friday's non-farm payrolls report to show that the American economy created 127,000 jobs in August, on top of 163,000 in July. The Fed holds its next meeting Sept. 13.
Canadian employment data is also being released Friday. It is believed that the economy cranked out 11,000 jobs last month.
Traders also looked ahead to Thursday and an announcement from European Central Bank president Mario Draghi. He is expected to announce details of a new bond-buying program intended to bring down the borrowing costs of countries such as Spain and Italy.
The plan is seen as a crucial step toward easing the European government debt crisis, which is increasingly hurting the continent’s economy.
"For all intents and purposes, we will just wait until Thursday when we see something from the ECB, or not see something from them," said Garey Aitken, director of equity research at Bissett Investment Management in Calgary, adding there is a danger that markets are expecting more than the bank can deliver.
"So often we come to these events with so much anticipation and walk away disappointed and that could very well be the case again here on Thursday."
Ahead of Thursday’s announcement, Moody’s Investors Service lowered its rating outlook for the 17-country region that uses the euro currency, as uncertainty over the European debt crisis grows and the stronger countries in the group could be hard-pressed to provide support.
Moody’s is revising its outlook to “Negative” from “Stable” for the European Union’s top Aaa credit rating. That means the rating could be downgraded, which would cost the EU more to borrow.
Canada's central bank will be in focus Wednesday as the Bank of Canada makes its next announcement on interest rates. The bank is expected to leave its key interest rate unchanged at one per cent, but traders will look for hints as to when it might hike rates.
There was also other negative economic news over the long Labour Day weekend.
China’s HSBC manufacturing Purchasing Managers Index fell to 47.6 in August from 49.3 in July, which was the lowest reading since March 2009.
However, there are signs that China's central bank is resisting calls for more aggressive measures to boost the economy based on past experience. Huge stimulus enacted in response to the 2008 global crisis fuelled inflation and a wasteful spending boom.
Meanwhile, the final read on the eurozone manufacturing PMI came in at 45.1 in August.
The energy sector dipped 0.6 per cent as oil prices backed off after the release of the U.S. data, with the October crude contract on the New York Mercantile Exchange down $1.17 at US$95.30 a barrel. Canadian Natural Resources (TSX:CNQ) lost 77 cents to C$29.22 while Suncor Energy (TSX:SU) gained 31 cents to $31.12.
The December copper contract on the Nymex was up one cent at US$3.47 a pound but the base metals sector lost 0.4 per cent. Teck Resources (TSX:TCK.B) fell 66 cents to C$26.58 and Major Drilling Group Intl. (TSX:MDI) shed 36 cents to $8.98.
The gold sector was down about 0.5 per cent with bullion up $8.40 to US$1,696 an ounce. Barrick Gold Corp. (TSX:ABX) lost 33 cents to C$37.68.
Financial stocks also weakened with National Bank (TSX:NA) off $1.21 at $72.80 while Bank of Montreal (TSX:BMO) gave back 52 cents to $57.10.
The health-care segment led advancers as investors also took in major acquisition activity.
Montreal-based Valeant Pharmaceuticals International Inc. (TSX:VRX) is buying U.S. dermatology products maker Medicis Pharmaceutical Corp. for about $2.6 billion in cash in a deal to strengthen its position in skin treatments and care.
Valeant said Monday that it is paying $44 per share for Medicis, a 39 per cent premium over Friday’s closing price of $31.87 for the Scottsdale, Ariz., company. Valeant stock ran up $7.47 or 14.8 per cent to $57.94.